The goal of the Health Services Research Core is to provide support for clinical, epidemiological, economic, and health services research requiring longitudinal HIV/AIDS patient information. Studies supported by the Core will address questions concerning clinical outcomes for persons with HIV/AIDS, patterns of services utilization and costs of care, and the cost-effectiveness of treatment innovations and models of health care delivery. Information generated from this research may be used to improve HIV/AIDS management strategies and inform health policy decisions. An HIV/AIDS database has been initiated under pilot funding from the University of Washington Harborview Medical Center. Funding of this Core will provide the necessary resources to develop the database into a comprehensive centralized repository of information on HIV/AIDS research. This population-based HIV/AIDS Data System will integrate information from clinical. administrative and billing systems. This will allow researchers to access and analyze computerized inpatient and outpatient medical record data including detailed information regarding AIDS-related diagnoses; laboratory values such as HIV-1 RNA level; pharmacy data including anti- retroviral therapies; procedures; service utilization and associated changes; mortality data; and patient-based assessment of quality-of-life and functional status. The Health Services Research Core will be the coordinating body for the development of the HIV/AIDS Data System and extraction of data for research projects. A committee made up of investigators providing expertise in the clinical care of HIV/AIDS patients, health services research, economics, pharmacology, epidemiology, and biostatistics will review proposed research projects for appropriate design and content with Core data. Specific proposals that have been reviewed include: 1) utilization of health care services and risk-adjusted costs of care for HIV/AIDS patients enrolled in publicly funded programs, and 2) cost- utility analysis of anti-retroviral therapy in a clinical practice setting. Health services research approaches to HIV/AIDS questions defined by Core investigators may be applied to other data sources at local, state, and national levels.